Studies on the purification of a lytic, anti-trypanosomal factor from the bacterial species, Pseudomonas fluorescens, were continued. Reversed-phase high performance liquid chromatography (HPLC) was used in our attempts to obtain fractions suitable for NMR and mass spectroscopic analyses. Although a considerably purified compound was obtained, structural analysis was complicated by the occurrence of Tris in the purified fractions. This chemical was present in the defined medium used for the cultivation of the bacterium and persisted through various chromatographic column elutions. After decontamination of the samples employing several procedures for Tris removal, NMR analysis disclosed the occurrence of glycosidic linkages in this antibiotic but further decontamination will be necessary to obtain a complete structural characterization. The determination of chemical structure is essential before studies on synthesis are initiated and pharmacological and toxicological properties are examined employing Trypanosoma cruzi infections.